Hydraulic Strategies and Response to El Niño Drought in Amazon Rainforest
Abstract
Variability of tree-scale carbon and water uptake strategies is increasingly recognized to be of paramount importance for understanding the limits of drought resilience of tropical rainforests. Here, we present evidence of such variations using a set of ecohydrologic data collected through the DOE "GoAmazon" project, with a specific emphasis on the response of a seasonal rainforest in eastern Amazonia to the strong 2015 El Niño drought. Data from 50 sapflow sensors are combined with high-frequency observations on stem and leaf water potential as well as precision dendrometry. The emerging behavior shows a spectrum of successfully co-existing hydraulic strategies, ranging from tight control against xylem failure to a near lack of regulation of the water flux through the stomata, implying the existence of other mechanisms to deal with extreme tissue dehydration. These strategies also exhibit coupling with tree growth patterns and dynamics of non-structural carbohydrates, with the latter type of trees allocating more carbon to growth and less to internal reserves, while the opposite is true for the former tree type. The results suggest a new approach for integrating hydraulic traits and carbon-cycle dynamics, and a strategy for mapping traits to function in the next generation of predictive models of ecosystem dynamics.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.B11B0453I
- Keywords:
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- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCESDE: 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 1813 Eco-hydrology;
- HYDROLOGYDE: 1818 Evapotranspiration;
- HYDROLOGY